Preheat your oven to 350°F (180°C). Line a 9×13-inch baking pan with parchment paper, leaving some overhang for easy removal later. Set aside.
In a large mixing bowl, combine the brownie mix, eggs, vegetable oil, and water. Stir until smooth, being careful not to overmix. Pour the batter into the prepared pan, spreading it into an even layer.
18 ounces family-size brownie mix, 2 large eggs, ½ cup vegetable oil, 2 tablespoons room temperature water
In a medium bowl, use a handheld mixer on low speed to beat together the cream cheese and powdered sugar for 1-2 minutes, or until smooth.
8 ounces cream cheese, ¾ cup powdered sugar
Mix in the vanilla extract, cold heavy cream, and all-purpose flour, continuing to blend until well combined.
1 teaspoon vanilla extract, ¼ cup cold heavy cream, 1 tablespoon all-purpose flour
Spoon heaping dollops of the cream cheese mixture over the brownie batter, leaving space between each dollop for the strawberry pie filling.
Repeat the process with the strawberry pie filling, adding dollops in between the cream cheese mixture. Ensure some brownie batter remains visible.
21 ounces can strawberry pie filling
Using a butter knife, gently swirl the cream cheese mixture and strawberry filling together, being careful not to disturb the brownie layer beneath.
Bake for 45-55 minutes, or until the center is set and a toothpick inserted into the brownie portion comes out almost clean. Avoid overbaking.
Allow the brownies to cool in the pan on the counter, then refrigerate for at least 3 hours, or up to overnight, before slicing and serving.